I have a 4112.016 American Standard Toilet and even with the floater all the way down the chain the water seems to keep running and going into the bowl.

1.The Flapper Valve isn't seating all the way, and allowing water to seep through. (At end of chain)
2.The Fluidmaster water control unit that is connected to the other end of the chain, isn't shutting off when the lever for it, is all the way in the down position.

Test the FluidMaster unit, by lightly applying pressure in a down motion, to that lever.
(Facing the toilet from the front, the FluidMaster water control unit is in the left corner of the tank. {Not trying to insult your intelligence}
The lever I speak of, is the small arm at the top of the FluidMaster. The Flapper Valve chain connects to this lever)

If it shuts off, you may have some fine sand, or other foreign material in the FluidMaster. [Taking one apart, and checking, then reassembling, is No fun!]

If it doesn't shut off when you apply pressure to that lever, you may have a bad diaphragm in the FluidMaster.
Suggest you replace this unit.

You can buy a replacement seal for the filler for about 85¢. Just turn off the water and turn the top counter clockwise about 30°.

The tank ball (Flapper) is replaceable for about $5. They just slide down, over the refill tube.